This invention relates to an electrical connector for electrically connecting two connection objects and, in particular, to an electrical connector suitable for transmitting a high-frequency signal, such as a digital signal, between two connection objects.
As an electrical connector of the type, there is known an electrical connector according to the HDMI (High-Definition Multimedia Interface, HDMI is a trademark or a trademark registration of HDMI Licensing, LLC) standard. Referring to FIGS. 1A, 1B, and 2, examples of use of conventional electrical connectors will be described.
Referring to FIG. 1A, a first example will be described. A right-angle connector 800 as a receptacle connector according to the HDMI standard (may simply be referred to as a HDMI receptacle connector) is mounted to a digital electronic apparatus 500 such as an optical disk recorder. The connector 800 serves to connect a peripheral apparatus (not shown) such as a digital display or an associated apparatus (not shown) such as a set-top box (STB) for cable television broadcasting to the digital electronic apparatus 500 through a plug harness 200 according to the HDMI standard (may simply be called a HDMI plug harness).
The electronic apparatus 500 comprises a casing 501, a main board 502, and a subsidiary board 506. The main board 502 and the subsidiary board 506 are disposed inside the casing 501. The kind of subsidiary board serves as an interface for contact pitch-converting between two electrical connectors connected to the subsidiary board.
On the main board 502 provided with a conductor having a circuit pattern, a receptacle connector 504 and various electronic devices (not shown) forming an electronic circuit and including a CPU (Central Processing Unit) are mounted.
On the subsidiary board 506 similarly provided with a conductor having a circuit pattern, the above-mentioned right-angle connector 800, various electronic devices including a digital transmission chip 503, and a receptacle connector 507 are mounted. The electronic devices are not illustrated in the figure except the digital transmission chip 503. The digital transmission chip 503 serves to perform bidirectional conversion between a signal according to a standard processed by the electronic circuit formed on the main board 502 and a signal according to the HDMI standard (may simply be called a HDMI signal).
Those elements, such as the connectors and the electronic devices, mounted on the main board 502 and the subsidiary board 506 are fixed to and electrically connected thereto by soldering leads, pins, or lands of the elements to corresponding lands formed on these boards.
The main board 502 and the subsidiary board 506 are connected to each other through a flexible flat cable (FFC) 505 having plug connectors formed at opposite ends thereof. Instead of the FFC 505, a flexible printed circuit (FPC) may be used. For convenience of assembling and maintenance of the electronic apparatus 500, the plug connector at one end of the FFC 505 is adapted to be removably fitted to the receptacle connector 504 mounted on the main board 502. Similarly, the plug connector at the other end of the FFC 505 is adapted to be removably fitted to the receptacle connector 507 mounted on the subsidiary board 506.
Referring to FIGS. 1B and 2, a second example will be described. The right-angle connector 800 as a HDMI receptacle connector is mounted to a digital electronic apparatus 600 in order to connect a peripheral apparatus (not shown) to the digital electronic apparatus 600 through the HDMI plug harness 200.
The electronic apparatus 600 comprises a casing 601, a main board 602, and a subsidiary board 606. The main board 602 and the subsidiary board 606 are disposed inside the casing 601.
On the main board 602 provided with a conductor having a circuit pattern, various electronic devices including a CPU and a digital transmission chip 603, and a receptacle connector 604 are mounted. The electronic devices are not illustrated in the figure except the digital transmission chip 603.
On the subsidiary board 606 similarly provided with a conductor having a circuit pattern, the above-mentioned right-angle connector 800 and a receptacle connector 607 are mounted.
Those elements, such as the connectors and the electronic devices, mounted on the main board 602 and the subsidiary board 606 are fixed to and electrically connected thereto by soldering leads, pins, or lands of the elements to corresponding lands formed on these boards.
The main board 602 and the subsidiary board 606 are connected to each other through a FFC 605 having plug connectors formed at opposite ends thereof. For convenience of assembling and maintenance of the electronic apparatus 600, the plug connector at one end of the FFC 605 is adapted to be removably fitted to the receptacle connector 604 mounted on the main board 602. Similarly, the plug connector at the other end of the FFC 605 is adapted to be removably fitted to the receptacle connector 607 mounted on the subsidiary board 606.
However, in various arrangements using the conventional electrical connectors of the type, including the examples illustrated in FIGS. 1A, 1B, and 2, impedance mismatching is caused to occur at a portion where the connector and the subsidiary board are connected to each other. Furthermore, the conductors on the subsidiary board, including the circuit pattern and the lands, are susceptible to noise and produce a crosstalk. This results in a problem that a digital signal as a high-frequency signal transmitted between the digital transmission chip and the connector is seriously degraded.
In addition, the electronic apparatus is desired to be simplified in structure, reduced in size, decreased in weight, and lowered in cost. Accordingly, the arrangement including the electrical connector and used in the electronic apparatus is desired to be further simplified in structure, further reduced in size, further decreased in weight, and further lowered in cost.